Using and understanding sedation scoring systems: a systematic review

To systematically review instruments for measuring the level and effectiveness of sedation in adult and pediatric ICU patients. We searched MEDLINE, EMBASE, the Cochrane Library and reference lists of the relevant articles. We selected studies if the sedation instrument reported items related to consciousness and one or more additional items related to the effectiveness or side effects of sedation. We extracted data on the description of the instrument and on their measurement properties (internal consistency, reliability, validity and responsiveness). We identified 25 studies describing relevant sedation instruments. In addition to the level of consciousness, agitation and synchrony with the ventilator were the most frequently assessed aspects of sedation. Among the 25 instruments, one developed in pediatric ICU patients (the Comfort Scale), and 3 developed in adult ICU patients (the Ramsay scale, the Sedation-Agitation-Scale and the Motor Activity Assessment Scale), were tested for both reliability and validity. None of these instruments were tested for their ability to detect change in sedation status over time (responsiveness). Many instruments have been used to measure sedation effectiveness in ICU patients. However, few of them exhibit satisfactory clinimetric properties. To help clinicians assess sedation at the bedside, to aid readers critically appraise the growing number of sedation studies in the ICU literature, and to inform the design of future investigations, additional information about the measurement properties of sedation effectiveness instruments is needed.